Here is a very simple biped I made just for fun. It is not walking nice yet, I have to play more with the code and at this moment it can't turn. More work needs to be done, but I had fun with it.Wobbly, a MiniBiped robot.

how many legs do you want, 2, 4, 6, 8. a 'walking robot can have any number of legs'

second is what size do you want to make it? do you want it the be the size of the robot Ro-Bot-x posted or do you want it to be 1' tall, 2' tall etc.

why are you making the robot and what do you have to focus on. e.g. come up with a new/smarter control software, come up with a better designed set of electronics for optimal operation, or increase the efficiency of the mechanical components?

I agree with blackbeard. due to the tri-gate walking sequence either applied mechanically like the example blackbeard gave or through software like on hexapods with 12 or 18 Degrees of freedom they are more stable in principle.

It also gives you a easy opportunity to pic levels of complexity by increasing or reducing the degrees of freedom in the robot has. e.g. 2 motors like given in the example from Blackbeard giving essentially 2 DOF, 1 servos per leg giving 6 DOF, 4 DOF in each legs as one of the Trossen Robotics Hexapods has giving 24 DOF.

ok actually i want to make 2 leg only.why i do the robot are the lecturer ask me to synchronize the leg just like human walk.i really dont have any idea.he said if i do more leg,there are lots of problem. it is about 15 cm.come up with a better designed set of electronics for optimal operation and good enough to walk like human.

most standard servos will fit the kits that are sold for this sort of thing. but be careful that you don't get some cheap Chinese servos as some can be really noisy(loud and jitter a lot) which is not at all suitable for this sort of platform.

If i was you i would look into the hitec servos as they are generally good quality and suitable for such a platform. a servo like the 'hitec HS-311' would work well for what you have planned. and they are relatively well priced in the US you can get them for app $8.90. but they go upwards form there. $8.90 is a really goo price for such a servo.

I used cheap chinese servos and on Wobbly I used these because they work as good as the hitec ones. They have less torque than the hitec equivalent, but that's the only con. They also fit perfectly the Lynxmotion micro servo brackets.

Another factor with cheap servos is that they tend to weigh considerably more(larger cheaper motor, less gears), so on a platform that uses lots of servo's you are going to have difficulties in the long run.

well the first specification to decide on would be degrees of freedom in each leg. this leads to what sort of frame you need, how many servos you need, what controller you want to use that can handle six servos etc. 3 is probably a good number as it provides enough control whilst staying small as the size you mentioned. the picture on the SoR biped engine page looks to be a 3DOF biped.

As for making it remote control, that should be simple. there are many ways that you can do that e.g. blue-tooth through the computer, interface an RC transmitter, over a RF module between two micro controllers.

there are many ways but it depends on how you want to interact with the robot. from my experience blue-tooth would be the easiest.

well depending on what micro controller you choose to be the main brains they have Blue-tooth modules that simply plug into a UART of the micro controller board. very simple to use. the main part of integrating blue tooth is in the programming.

if you go with the axon micro controller all you need to do is plug it directly into one of the UART ports provided and program it. there are numerous examples of using the blue smirf module with the axon that are available.

All you need to power the biped is a 6v battery with a higher mAh rating. i would say 1800 mAh or higher for your application.

the reason i keep suggesting the axon is that the majority of the electronics is 'plug and play' and as for the code much of the structure is there you just have to add the code to get the biped to do what you want it to.